52 Proceedings of Royal Society of Edinburgh. [sess. 
very definite features about these bodies which are quite constant, 
and which it is not easy to conceive could be constant on the 
hypothesis of a purely mineral origin. 
Under these circumstances, I sent a series of the specimens to 
Mr Etheridge, the skilled palaeontologist of the British Museum, for 
his opinion and determination. He at once pronounced decidedly 
against my preconception of a vegetable origin. After the most 
careful and prolonged examination, however, with all the light 
which could be thrown upon the question by specimens from all 
parts of the world, Mr Etheridge has come to the conclusion, 
without the smallest doubt, that the bodies found in the Loch 
Fyne quartzite are the tubes or burrows of annelids, similar in 
their nature and origin to those which have been long familar in 
the same rock as it occurs in Sutherland and Ross. This verdict 
was supported by arguments, by specimens, and by further investi- 
gations on the spot, which have carried complete conviction to my 
own mind that I was entirely led off the true scent when I thought 
of vegetable organisms, and that, although in a somewhat new and 
certainly unexpected form, I had, after all, found what was the 
original object of my search, namely, the repetition in our south- 
western beds of quartzite of those remarkable annelid borings which 
are so abundant in the north. One specimen from the quartzite of 
Quenaig, in Sutherland, was almost of itself sufficient to satisfy me 
that Mr Etheridge had recognised the true interpretation. It ex- 
hibited a cross section of the well-known annelid tubes of that county 
in a fresh fracture of the rock ; and these cross sections presented pre- 
cisely the same ovate tubes, with precisely the same defining ring 
of red oxide of iron. The phenomena are identical. But the inter- 
pretation is confirmed by many other facts, and converging considera- 
tions. I will now shortly sum up the arguments which seem to 
me to be tolerably conclusive on this matter. I give them in the 
order in which they range themselves in my own mind — without 
laying any stress upon the authority of Mr Etheridge — although, in 
passing, I may say that in questions such as this, namely, the 
interpretation of appearances which are of necessity obscure, I 
attach immense importance to the perceptions of a trained and 
experienced eye. It acquires an education, and an insight of its 
own. Interpretation becomes almost instinctive, from that kind of 
